1. Field of the Invention
The present invention relates to a room temperature-curable resin composition, a cured material of which has good residual tack on its surface, and improved adhesion of coatings which are applied on the surface of the cured material, and a method for improving the adhesion of coatings to a cured material of a curable resin composition.
2. Description of the Prior Art
A group which has a hydroxy or hydrolyzable group bonded to a silicon atom and is crosslinked through the formation of a siloxane bond (hereinafter referred to as "silicon-containing reactive group) means a group which is hydrolyzed with water in an air and generates a siloxane bond (Si--O--Si) through --Si(OH).sub.3, etc. with a silanol condensation reaction with other silicon-containing reactive group. A typical example of the silicon-containing reactive group is one represented by the formula: --Si(OCH.sub.3).sub.3, which forms the siloxane bond as follows: ##STR1##
Thus, polymers having the silicon-containing reactive groups are crosslinked and cured in the presence of moisture even at a room temperature.
Among such the polymers, those comprising oxyalkylene polymer backbones such as polyoxypropylene backbones are widely used as construction sealing materials, industrial sealing materials and the like by making the use of their properties that they are highly viscous liquids at a room temperature and cured to provide a rubbery elastomers.
The sealing materials are filled in gaps between construction materials such as wall panels or tiles and cured, and cured materials stop up the gaps for maintaining water- and air-tightness.
In some cases, it is desired to apply coatings on the surface of the cured material, but the adhesion between the coatings and the surfaces of the cured sealing materials is insufficient, particularly when solvent type-coatings are used. In addition, the surfaces of the cured materials have slight tackiness, that is, residual tack, and therefore contaminated with dusts and the like.